It is conventional to control various appliances in the home such as TV's, VCR's, and other types of appliances by infrared remote control units. However, such controls must be located in a line of sight of the equipment to be controlled. And while there are several remote control units on the market which consolidate the functions of several remote controls into a single unit, they also suffer from the requirement of having to be within line of sight of the appliance being controlled.
The present invention is directed to the control of a plurality of infrared controlled appliances from a single UHF radio remote control. The present apparatus provides full control of all house appliances from anywhere in the house from only a pocket-size remote UHF controller. The present device provides a single hand-held radio frequency remote controller and a radio frequency to infrared converter or transponder unit located in the line of sight of the appliances to be controlled. Therefore, the present invention allows control of the appliances from anywhere within the receiver range of the transponder unit which is typically 200 feet.
The present invention allows, for example, a VCR located in the living room to be controlled from a bedroom where a second television may be located and eliminates the need for a second VCR in the bedroom. Similarly, in a household with an infrared controlled stereo system with remotely located speakers, the volume of the stereo can be controlled from any room in the house.
On the other hand, the direct control of an appliance by a UHF remote controller is not feasible. Virtually all infrared remote control systems use a carrier frequency of between 10 KHz and 75 KHz. This carrier is then amplitude modulated in various fashions to transmit the digital data required for control. As a result of the carrier frequency, and the sometimes high data rate, simple AM modulation of the infrared code (including the carrier and the data), onto a UHF radio frequency carrier, would result in an occupied band width which would exceed the FCC rules for this type of device and would require excessive output power.
The present invention avoids the problems of the prior art by storing in the transponder the information necessary to replicate or mimic the infrared code for operating the various appliances. The UHF radio remote controller is then able to transmit a narrow-band data signal to the transponder identifying a particular infrared code. The transponder then transmits the infrared code sequence to the appropriate appliance.